1. Field of the Invention
The present invention relates to a broadcast receiving method and relates to a broadcast receiving apparatus, wherein program-related information such as sound and moving pictures are transmitted as a broadcast.
2. Description of the Related Art
There is provided a digital broadcasting system that broadcasts digitally coded programs comprising sounds and moving pictures through a satellite or a cable. The digital broadcasting system can simultaneously transmit a large capacity of programs which is twice to ten times larger than regular analog transmission system does in a given transmission band by using several digital techniques such as compression encoding of sounds and moving pictures, packet multiplexing, and high efficiency digital modulation encoding.
The digital broadcasting system can handle many program service channels which are twice to ten times more than regular analog transmission does in one transmission channel having same transmission band. Further, a number of program service channels and a number of programs can drastically be increased by a frequency multiplexing method in a plurality of transmission channels as a broadcasting system.
Program selection by a listener or a viewer poses new problems since the number of program channels and the number of programs have been increased. The listener or the viewer is obliged to spend his time to select date and time of broadcasting and program service channel of desired programs to be listened or to be watched from a program chart listed on a newspaper or a magazine.
In addition thereto, in a current system for a fee-related restriction to listening to or to watching at a program channel by channel or in a current system for charging for a program to be listened or to be watched channel by channel, it is impossible to manage minutely restriction to listening to or to watching at each program such as movies and sports or to manage precisely a fee charging system for listening to or watching at each program.
Accordingly, to improve the above mentioned problem, there provided a system which transmits program-related information such as contents of program, broadcasting schedule, restriction to listening or watching, and charging for each program in conjunction with encoded data of sounds and moving pictures. On the other hand, a receiving apparatus is provided to indicate or inform the broadcasting schedule, to manage the restriction to listening or watching, or to manage the fee charging system in accordance with the program-related information. However, the program-related information such as contents of program and broadcasting schedule require extension of transmission period to improve program selection, so that a total volume of information is increased by the extension of transmission period.
With assuming that a volume of program-related information is 128 bytes and a number of programs per day per one service channel is 48 programs and a number of total service channels of digital broadcasting service is 100 channels and a transmission period is 2 weeks (14 days), the total volume of information becomes about 8.5 Mbytes. Therefore, memory capacity of a storage device for the program-related information of the receiving apparatus is necessary to be increased, or a method, which periodically transmits information and selectively receives necessary information, is adopted.
In the case of increasing memory capacity, it causes new problem that a cost of the receiving apparatus is increased. In the case of selectively receiving information, a process of program selection operation based on the program-related information is delayed. Furthermore, a transmission volume per unit time for the program-related information increases, if the period of periodical transmitting information is shortened to improve the latter case.